Envelope for tobacco goods

ABSTRACT

An improved cigarette envelope comprising a mixture of highly methylated methyl cellulose, acetyl cellulose, a filler agent, and a softener agent. According to the preferred process described in the disclosure, the mixture is prepared by using the above mentioned materials in a suspension wherein the solvent is a mixture of methylene chloride and methanol and in which the acetyl to methyl cellulose is in the ratio of 4:1 to 20:1 and the suspension is dried by gradually increasing the temperature in at least three zones.

1451 Jul 30, 197.4

ENVELOPE FOR TOBACCO GOODS Inventors: Ernst-Rolf Detert, Lubbecke,

Westfalen; Wilhelm Ruchholz, Obermehnen, both of Germany Eduard Gerlach, Gmbll Chemische Fabrik, Lubbecke, Germany Filed: Jan. 22, 1973 Appl. No.: 325,724

Related US. Application Data No. 83,658, Oct. 23, l970,

Assignee:

abandoned.

Foreign Application Priority Data Feb. 21, 1970 Germany 2008150 US. Cl. 131/140 C, 131/15 Int. Cl A24b 3/14 Field of Search 131/140, l5, 17

References Cited UNITED STATES PATENTS 10/1961 'Grunwald 131/140 3/1962 Grossteinbeck et a1. 131/140 C 3,025,860 3,062,688 1 1/1962 Detert et al 131/140 C 3,500,833 3/1970 Halter et a1. 131/140 C Primary Examiner-Melvin D. Rein Attorney, Agent, or Firm-Molinare, Allegretti, Newitt & Witcoff [57] ABSTRACT An improved cigarette envelope comprising a mixture of highly methylated methyl cellulose, acetyl cellulose, a filler agent, and a softener agent. According to the preferred process described in the disclosure, the mixture is prepared by using the above mentioned materials in a suspension wherein the solvent is a mixture of methylene chloride and methanol and in which the acetyl to methyl cellulose is in the ratio of 4:1 to 20:1 and the suspension is dried bygradually increasing the temperature in at least three zones.

I 9 Claims, No Drawings 1 ENVELOPE FOR TOBACCO GOODS This is a division of application Ser. No. 83,658, filed Oct. 23, 1970, now abandoned.

BACKGROUND AND SUMMARY OF THE INVENTION In a conventional cigarette, the cut tobacco (i.e., the so-called inlay) is held together by a cylindrical paper covering or envelope. The fabrication of the cigarette takes place with the aid of suitable cigarette machines which operate on an extrusion process (Strangverfahren). That is, the inlay is brought onto an endless paper strip which is closed into a cylinder with the aid of a glue strip. The glue used for the gluing of the cigarette envelope is predominantly built up on dextrin. Upon leaving the machine, the envelope is cut to the desired length to form a cigarette.

According to the usual paper production process, the special paper used for the cigarette envelope is prepared from an aqueous suspension of cellulose fibers. Alkali nitrates and mineral white bodies are also added for burning control and brightening.

The use of such cigarette paper has given cigarettes a characteristic and aesthetic appearance which consumers nowadays demand. The paper covering has, however, resulted in drawbacks, hitherto taken for granted. For example, the high cellulose content of the paper has a considerably adverse effect on the taste of the tobacco smoke. The tar development from the paper in the smoking process is appreciable. The formation of the envelope requires a glue which has a negative effect on the smoke flavor. g

The unhealthful effects of cigarette smoking have recently been violently attacked. For example, health authorities in the U.S.A. now require health-waming on the cigarette packages. Accordingly, it would be desirable to have an envelope for cigarettes which does not affect taste and which is capable of reducing the tar and nicotine content of the smoke, while preserving the appearance and mechanical properties of conventional envelope material.

The applicants have surprisingly discovered that it is possible to produce an envelope having the foregoing properties by fabricating the envelope from highly methylated methyl cellulose and acetyl cellulose. Ac-

cording to the preferred process described herein, the

methyl cellulose-acetyl cellulose envelope is fabricated by preparing a suspension comprising methylene chloride and methanol as solvents, a white pigment, such as titanium dioxide, and fillers and softeners. The suspension is dried in several stages to a porous sheet, in which process the drying temperature in the first stage lies above the boiling point of the methylene chloride, and in the last drying stage above the boiling point of the methanol, but not so high that the sheet sinters.

Use of the applicantsdiscoveries results in several important advantages. For example, the use of methyl cellulose increases the elasticity of the envelope in the moistened state (i.e., makes the envelope more like tobacco). Surprisingly the mixture of methyl cellulose and acetyl cellulose in certain amounts brings about a restriction of the shrinkage effect of the envelope and in particular, a development of a porosity of the envelope which is known to be advantageous for the smoking process. This effect is particularly surprising bemethyl groups per beta glucoside linkage in the cellu-' cause the acetyl cellulose derivative is ordinarily in compatible with a methyl cellulose derivative.

Applicants have also discovered that the sealing characteristic of pure acetyl cellulose films remains preserved despite the presence of a large amount of filler and unsealable methyl cellulose. Therefore, for

the first time in the fabrication of cigarettes or similar smoking articles, it is possible to use a heat-seal process, and thereby eliminate the taste-disturbing glue strip, without creating production difficulties.

Applicants have also discovered that an admixture of tobacco and white inorganic pigments interact with the solvent mixture and the softeners described herein, to achieve a flotation effect. According to this effect, the white pigments having a high specific gravity, are conveyed to the surface, and the dark tobacco parts, if present, having a lower specific gravity, are brought into the base surface of the envelope. Thus, cigarette envelopes with an appreciable constituent of tobacco can be produced in one operation, and still retain their customary white appearance.

Applicants have also found that a high proportion of mineral white bodies in the envelope tends to reduce tar formation from the envelope.

Applicants greatest discovery is that a tobacco inlay surrounded with an envelope made according to the present invention produces significantly less tar and nicotine in the smoke than an equivalent inlay surrounded by a conventional envelope material.

Additional advantages andfeatures of the invention are described in the following section of the application.

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the preferred embodiment, the proportion of highly methylated methyl cellulose in the cellulose mixture lies in the range of 1 part of methyl cellulose to 4 to 20 parts of acetyl cellulose. By highly methylated methyl cellulose, we mean a methyl cellulose having in the range of from about 30 to 39 percent lose molecule. By acetyl cellulose we mean cellulose having in the range of from about 30 to 40 percent acetyl groups per beta glucoside linkage in the cellulose molecule.

EXAMPLE 1 WHITE ENVELOPE FOR CIGARETTES In a stainless, seal'able agitating tank, introduce under agitation 445 parts by weight of methylene chloride and a mixture of seven parts by weight of highly methylated methyl cellulose and 26 parts by weight of acetyl cellulose. The ratio of highly methylated methyl cellulose to acetyl cellulose can fluctuate in a range from about I to 4 to about I to 20 and is largely determined by the type of cigarette envelope desired, by the type and variety of the tobacco used, and by the size of the finished envelope. Then introduce 26 parts by weight of fine-ground tobacco (grain size about microns), which acts as a filler agent, and 20 parts by weight of titanium dioxide, which acts as a white pigment. Into this suspension allow to run under constant agitation 50 parts by weight of methanol.

After the suspension has swelled, add nine parts by weight of a softener agent consisting of one part by weight of glycerin, four parts by weight of propylene glycol, and four parts by weight of butylene glycol. Mix well and homogenize.

EXAMPLE 2 Brown Envelope For Cigarettes Or Cigarillos parts by weight Methylene chloride LItLII Since this envelope is to have a tobacco-like appearance and not the white of the conventional cigarette envelope, the constituent of the white-coloring pigment, namely titanium dioxide, has been omitted and replaced by a mineral or inorganic filler agent comprising mica and calcium carbonate, which do not color, but contribute to reducing the tar formation. Talc or other inorganic filler agents could also be used. The above-listed ingredients are worked in the manner described in Example 1 into a homogeneous composition.

EXAMPLE 3 The production of an envelope of the composition described in Example 1 proceeds as follows:

With the aid of a casting (pouring) apparatus, the well-homogenized composition stored under the exclusion of air, according to Example 1 is uniformly applied onto an endless high-grade steel band in a sufficient layer thickness and is conducted through a drying channel. The porosity of the envelope can be increased to an optimum by forming the drying channel of the envelope casting machine in such a way that several drying stages are present with differing temperatures. The formation of the porosity can be further heightened if methyl glycol (CH -O-CH CH -OH) or ethyl glycol (C H -O-CH -CH -OH) is added to the composition in an amount of up to the amount of the softener constituent. To best achieve this effect, ten parts by weight of methyl glycol or ethyl glycol are added to the compositions of Example 1 or Example 2. This amount generally comprises 1 to 6 percent of the composition of Example l as ready for the casting apparatus.

It is necessary in the first drying stage to exceed the boiling point of the methylene chloride and in the last drying stage to choose the temperature in such a way that it lies higher than the boiling point of the methanol. In the last drying stage, however, it must not be so high that the very important micropores of the envelope that have arisen during the drying sinter together. A preferred channel has four temperature zones. The drying temperature in the first zone lies above the boiling point of the methylene chloride, which is 41.6C, and in the range from 45 to 55C. The temperature in the second zone lies between 55 and 60C. The temperature in the third zone lies between 60 and 65C, and the temperature in the fourth zone lies above the boiling point of methanol, namely, between 65 and 75C.

Different envelope thicknesses are produced depending on the thickness of the composition. Especially well suited are envelopes with a dry weight of 30 to 60 grams per square meter. The envelope leaving the drying channel is entirely free of solvents. The dried envelope which is continuously produced in great lengths is rolled onto rolls, which with the aid of a cut-off machine, are divided into small reels of the desired width. This step can also be carried out directly on the casting machine with corresponding currently available devices.

EXAMPLE 4 An envelope may be made by applying to the Example 2 composition the process described in Example 3.

The production of heat-sealed cigarettes from the previously prepared envelope proceeds as follows. The I envelope is rolled to a width of about 29 mm on a reel. The reel is clamped onto a cigarette machine in place of a roll of conventional cigarette paper. Apparatus for guidance, course, and any desired imprinting is the same as used with standard paper reels. The glue applicator is removed. The heatable iron bar or the endless heated steel band, which otherwise serves for the drying of the glue strip, is used for sealing the .foil. The temperature of the bar or of the band is adapted to the performance of the cigarette machine and the layer thickness of the envelope, and may be easily determined by those skilled in the art.

COMPARATIVE EXAMPLES 5-7 Corresponding comparative tests were carried out by standard smoke analyzing techniques as follows:

EXAMPLE 5 Brand A A popular King Size filter cigarette Nicotine in the smoke (one cigarette) 1.05 mg Tar products in the smoke (one cigarette) 16.50 mg Test cigarette comprising an inlay from a Brand A cigarette and an envelope made according to Example 3 hereof Nicotine in the smoke (one cigarette) 0.74 mg Tar products in the smoke (one cigarette) 10.90 mg EXAMPLE 6 Brand B A less popular cigarette with a cut-off filter Nicotine in the smoke (one cigarette) 0.45 mg Tar products in the smoke (one cigarette) 12.92 mg Test cigarette comprising an inlay from a Brand B cigarette and an envelope made according to Example 3 hereof Nicotine in the smoke (one cigarette) 0.43 mg t iarillo co 'sin n 'nla fro 1.; I cigarillo and an envelope made according to Example 4 hereof Nicotine in the smoke (one cigarillo) 0.53 mg Tar products in the smoke (one cigarillo) 11.45 mg Those skilled in the art will also recognize that the compositions and apparatus disclosed herein are merely exemplary of the preferred practice of the invention which is defined by the appended claims.

What is claimed is: i I characterized as comprising the product of: A P Q envelope ',m plioductsv fofmed a. mixing the methylene chloride, methanol, the by the drymg of a Suspenslon compnsed of: h highly methylated methyl cellulose, actyl cellulose,

methylated methyl cellulose, acetyl cellulose, a solventi mixture of methylene chloride and methanol, a tiller; 5 agent and a softener agent, the ratio of the acetyl cellu-. lose to the methyl cellulose being in the range of 4:1 to 20:1, the drying being conducted in a stepwise fashion by gradually increasing the drying temperature and removing the solvents while the suspension is being dried in a range of 45C to 75C to dry said suspension, said envelope having the properties of restricted shrinkage and reduction of tar and nicotine content of tobacco products smoke.

2. An. envelope according to claim 1, wherein the filler agent comprises tobacco meal.

3. An envelope according to claim 1, wherein thefiller agent comprises calcium carbonate and mica.

4. An envelope according to claim 1, wherein the z r l d b st yl r l glyi ii glycerm, propylene glycol and reduction of tar and nicotine content of to- S. An envelope according to claim 1, and further -l199299i$1959; comprising a porosity agent in an amount up to the 9. An envelope for tobacco products as in claim 8, amount 0f the Softener agent Present I wherein the sheet is passed through four drying zones An envelope according to claim 5, wherein the P9- 1 wherein the temperature in the first zone lies in the agent comprises methyl glycol ethyl glycol range from 45 to 55C., the temperature in the second an amount of from about 1 to 6 Percent of the total zone lies in the range from 55 to 60C., the temperafiller agent and softener agent to form the suspension; b. casting said suspension in the form of a thin sheet;

c. drying the sheet in at least two drying zones wherein the temperature in the first zone exceeds the boiling point of the methylene chloride to re- W rngvgsaid solvents from the sheet; and

d. drying the sheet in the last drying zone wherein the 15 temperature exceeds the boiling point of the methanol, but below the temperature at which the sheet sinters, to remove said methanol and methylene chloride from the sheet and to produce a porous, heat sealable envelope free of solvent, said envelope having the properties of restricted shrinkage.

composition ture in the third zone lies in the range from 60 to A fobacco Product compnsmg m 65C., and the temperature in the fourth zone lies in the tamed in an envelope of the composition of claim 1. range from to 750C.

8. An envelope for tobacco products as in claim 1 

2. An envelope according to claim 1, wherein the filler agent comprises tobacco meal.
 3. An envelope according to claim 1, wherein the filler agent comprises calcium carbonate and mica.
 4. An envelope according to claim 1, wherein the softener agent comprises glycerin, propylene glycol and butylene glycol.
 5. An envelope according to claim 1, and further comprising a porosity agent in an amount up to the amount of the softener agent present.
 6. An envelope according to claim 5, wherein the porosity agent comprises methyl glycol or ethyl glycol in an amount of from about 1 to 6 percent of the total composition.
 7. A tobacco product comprising a tobacco inlay retained in an envelope of the composition of claim
 1. 8. An envelope for tobacco products as in claim 1 characterized as comprising the product of: a. mixing the methylene chloride, methanol, the highly methylated methyl cellulose, actyl cellulose, filler agent and softener agent to form the suspension; b. casting said suspension in the form of a thin sheet; c. drying The sheet in at least two drying zones wherein the temperature in the first zone exceeds the boiling point of the methylene chloride to remove said solvents from the sheet; and d. drying the sheet in the last drying zone wherein the temperature exceeds the boiling point of the methanol, but below the temperature at which the sheet sinters, to remove said methanol and methylene chloride from the sheet and to produce a porous, heat sealable envelope free of solvent, said envelope having the properties of restricted shrinkage and reduction of tar and nicotine content of tobacco products smoke.
 9. An envelope for tobacco products as in claim 8, wherein the sheet is passed through four drying zones wherein the temperature in the first zone lies in the range from 45* to 55*C., the temperature in the second zone lies in the range from 55* to 60*C., the temperature in the third zone lies in the range from 60* to 65*C., and the temperature in the fourth zone lies in the range from 65* to 75*C. 